Severe Thunderstorm Warning 21, NWS Tucson, AZ

000 
WWUS55 KTWC 090018
SVSTWC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
518 PM MST TUE JUL 8 2008

AZC019-090030-
/O.CON.KTWC.SV.W.0021.000000T0000Z-080709T0030Z/
PIMA AZ-
515 PM MST TUE JUL 8 2008

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM MST
FOR NORTH CENTRAL PIMA COUNTY...

AT 512 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE AN ARE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING 
DAMAGING WINDS IN EXCESS OF 60 MPH AND VERY HEAVY RAINFALL. THESE 
STORMS WERE LOCATED FROM JUST SOUTH OF ORO VALLEY TO ACROSS 
INTERSTATE 10 SOUTH OF MARANA TO THE PICTURE ROCKS AND SILVER BELL 
AREAS...MOVING WEST AND SOUTHWEST NEAR 10 MPH.

LAT...LON 3215 11137 3250 11152 3251 11096 3231 11080
TIME...MOT...LOC 0015Z 049DEG 6KT 3229 11128

$$

MEYER

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
232 PM MST TUE JUL 8 2008

.SYNOPSIS...A SLOW MOVING LOW PRESSURE SYSTEM OVER SONORA WILL
GRADUALLY MOVE NORTH INTO ARIZONA THROUGH THURSDAY...WHERE IT WILL
EVENTUALLY STALL OUT UNTIL THE WEEKEND. THIS COMBINED WITH AN
INCREASE IN MONSOON MOISTURE WILL LEAD TO MORE NUMEROUS
THUNDERSTORMS...SOME OF WHICH COULD POSE A THREAT FOR HEAVY RAIN. A
SLIGHT DECREASE IN ACTIVITY IS EXPECTED FOR THE BEGINNING OF NEXT
WEEK ONCE THIS LOW PRESSURE AREA WEAKENS...AND HIGH PRESSURE BUILD
IN FROM THE EAST.

&&

.DISCUSSION...CONCERNING OUR TSTMS TODAY...WE ARE IN A BIT OF A
FIGHT BETWEEN INCREASING UPPER LEVEL DYNAMICS VERSUS RATHER WARM
TEMPS ALOFT AND SOMEWHAT LIMITED INSOLATION. STRONGEST TSTMS SO FAR
HAVE BEEN WHERE WEVE HAD THE MOST SUN TODAY...NAMELY ALONG THE RIM.
WE WILL HAVE TO WATCH THOSE...BUT OF GREATER CONCERN FOR LATER THIS
EVENING ARE THE TSTMS FLARING ON VORT SPOKES ROTATING NW AHEAD OF
OUR MID AND UPPER LEVEL LOW OVER SONORA. THIS LOW WILL BE THE KEY
FEATURE OVER THE NEXT SEVERAL DAYS AS MODELS...KEEPING IN MIND THEIR
POOR INITIALIZATION OVER MEXICO...HAVE BEEN QUITE CONSISTENT IN
BRINGING THIS NORTH AND STALLING IT OVER AZ LATER THIS WEEK. IN THE
SHORT TERM...HAVE ELECTED TO BUMP POPS UP A BIT OVER THE S 1/3 OF
THE CWA...ESPECIALLY OVERNIGHT WHEN INCREASING MOISTURE AND DYNAMICS
SHOULD MAINTAIN AT LEAST SOME NOCTURNAL DEVELOPMENT. HELD POPS AS-IS
EVERYWHERE ELSE...ALTHOUGH I WAS A BIT TEMPTED TO LOWER THEM FROM
KTUS NW INTO PINAL COUNTY TONIGHT. EVEN THOUGH CAPE IS ON THE WEAK
SIDE /500-1000 J/KG/...WE ARE STARTING TO SEE A BIT OF E SHEAR. THAT
COULD POSE SOME THREAT OF A HYBRID MICROBURST OR TWO...AND PERHAPS
SOME CLUSTERING INTO HEAVY RAINERS LATER IN THE EVENING.

WED-FRI CONTINUE TO LOOK QUITE A BIT MORE ACTIVE. AN UPPER LOW OR
SHEAR AXIS GETTING STUCK BETWEEN RIDGE CENTERS IS A TRADEMARK
TYPE-III SEVERE WEATHER/FLASH FLOOD PATTERN FOR ARIZONA. JUST TO ADD
TO IT...SOME SORT OF A MOISTURE SURGE IS WORKING UP THE GULF OF CA
BASED ON PRECIP WATER AND SATELLITE IMAGERY...ALONG WITH A
FORTUITOUS QUIKSCAT PASS EARLIER IN THE DAY. THUS THE 1.4-1.8
PRECIP WATER BOTH NAM AND GFS SHOW OVER SE AZ BY WED AFTERNOON
SHOULD PAN OUT. WITH A WARM CORE NEARLY STATIONARY LOW ON TOP OF
SUCH HIGH PRECIP WATER...YOU HAVE THE INGREDIENTS FOR A POTENTIAL
SHARS /SUBTLE HEAVY RAINFALL SIGNATURE/ EVENT...SOMEWHERE AT SOME
POINT. THE PROBLEM IS THAT THESE OUTBREAKS CAN OCCUR ANY TIME DAY OR
NIGHT...AND THE DIURNAL CYCLE CAN BE DISRUPTED TO THE POINT THAT OUR
HIGH POP FORECASTS CAN WIND UP IN THE WRONG TIMES OR PLACES. WHILE
CONFIDENCE IS GROWING FOR WIDESPREAD PRECIP...THE TIMING AND
PLACEMENT ARE BOTH FAR FROM CERTAIN. WARM TEMPS ALOFT AND LIMITED
SOLAR HEATING COULD ALSO THROW THINGS OFF KILTER. THUS WE HAVE
RAISED POPS...BUT NOT AS HIGH AS WE MAY EVENTUALLY NEED THEM TO BE.
SAME THINKING GOES FOR ADDING HEAVY RAIN WORDING TO THE GRIDS OR
ZONES -- IT IS SIMPLY TOO EARLY. AS AN INITIAL GUESS...WE LEANED ON
THE SPC-CALIBRATED SREF...WHICH PLACED A SLIGHTLY GREATER THREAT
OVER THE E CWA WED...CENTRAL CWA THU...AND THE WEST THU NIGHT/FRI.
THE GREATEST THREAT OF WET MICROBURSTS MAY BE WED AS WE RETAIN A BIT
OF DRY AIR ALOFT AND WE MAINTAIN RESPECTABLE E FLOW. SWODY2 LOOKS
GOOD IN THIS REGARD. ONCE WE SATURATE AND THE LOW MOVES OVERHEAD...
THAT PARTICULAR THREAT SHOULD DIMINISH AS THE HEAVY RAIN THREAT
INCREASES. THANKS TO HPC ON THE AREAL QPF AND QPFPFD COORD TODAY.

MODELS ARE PREDICTABLE IN THEIR UNPREDICTABILITY IN THE EXTENDED
RANGE. BY THEN THE GFS IS LITTERED WITH CONVECTIVE VORTICES WHILE
THE MID/UPPER LEVEL SHEAR AXIS BECOMES BROADER BUT REMAINS OVERHEAD.
GENERALLY WENT WITH THE ENSEMBLE MEAN WHICH INDICATES A GRADUAL
BREAKDOWN OF THE HIGH TO OUR NW...AND A WESTWARD EXPANSION OF THE
HIGH TO OUR E. IF THAT WORKS OUT...IT WOULD RETURN US TO A MORE
TYPICAL MONSOON PATTERN FOR MID JULY. WILL GRADUALLY SHADE POPS DOWN
TOWARD MID JULY CLIMO FROM DAYS 4 THRU 7...WHILE BRINGING BACK A
MORE DIURNAL TSTM CYCLE.

&&

.FIRE WEATHER...AN UPPER LEVEL LOW IS FORECAST TO STALL NEAR OR OVER
ARIZONA FOR THE REST OF THE WEEK. THIS...IN ADDITION TO INCREASING
MOISTURE FROM THE SOUTH...SHOULD RESULT IN HIGH HUMIDITIES AND
RATHER WIDESPREAD WETTING RAINS...ESPECIALLY FROM WEDNESDAY
AFTERNOON INTO FRIDAY.

&&

.AVIATION...SCATTED TSTMS WITH 6-8K FT AGL BASES WILL CONTINUE TO
DEVELOP AND SPREAD W THIS AFTERNOON AND EVENING. WHILE THE ACTIVITY
WILL DIMINISH BY 06Z...THERE IS A RISK OF REDEVELOPMENT OVERNIGHT...
PARTICULARLY NEAR KOLS AND KDUG. WINDS ARE EXPECTED TO BE 5-10 KTS
AND GENERALLY FROM THE SOUTHEAST EXCEPT NEAR THUNDERSTORMS THROUGH
06Z WHERE A FEW GUSTS OVER 40KTS ARE POSSIBLE. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

PYTLAK

WEATHER.GOV/TUCSON

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
122 PM MST TUE JUL 8 2008

AZZ019-029-030-032>035-091200-
NORTHERN GREENLEE COUNTY-SOUTHEAST PINAL COUNTY-
UPPER GILA RIVER VALLEY-TOHONO OODHAM NATION-
TUCSON METRO/MARANA/GREEN VALLEY-SANTA CRUZ COUNTY-COCHISE COUNTY-
122 PM MST TUE JUL 8 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
ARIZONA AND SOUTHEAST ARIZONA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER SOUTHEAST
ARIZONA THIS AFTERNOON AND GRADUALLY SPREAD WEST INTO THE DESERTS
THIS EVENING. OTHER THUNDERSTORMS DEVELOPING OVER THE SIERRA MADRES
IN SONORA MEXICO ARE THEN EXPECTED TO SPREAD NORTHWEST INTO MAINLY
SANTA CRUZ AND COCHISE COUNTIES OVERNIGHT. THE ATMOSPHERE IS A BIT
MORE UNSTABLE COMPARED TO YESTERDAY...SO A COUPLE OF STORMS COULD
PRODUCE WIND GUSTS APPROACHING SEVERE LIMITS. TEMPERATURES ALOFT ARE
RATHER WARM...SO THE RISK OF HAIL IS LOW. MOISTURE IS BEGINNING TO
INCREASE FROM THE SOUTH...SO A FEW STORMS MAY PRODUCE 1 TO 2 INCHES
OF RAIN IN A SHORT PERIOD OF TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A SIGNIFICANT INCREASE IN THUNDERSTORMS IS EXPECTED BEGINNING ON
WEDNESDAY AND CONTINUING INTO AT LEAST FRIDAY. A SURGE OF MOISTURE
IS SPREADING NORTH UP THE GULF OF CALIFORNIA...WITH A LOW PRESSURE
SYSTEM EXPECTED TO STALL OVER SOUTHERN ARIZONA BY THURSDAY. THIS
WILL INCREASE THE THREAT OF HEAVY RAIN AND FLASH FLOODING OVER
PARTS OF SOUTHEAST ARIZONA...WITH A FEW WET MICROBURSTS POSSIBLE
MAINLY ON WEDNESDAY. IT IS TOO EARLY TO TELL EXACTLY WHERE THE
HEAVIEST RAINS WILL FALL...BUT ISOLATED AMOUNTS OF 2 TO 4 INCHES ARE
NOT OUT OF THE QUESTION AT SOME POINT BETWEEN WEDNESDAY AFTERNOON
AND FRIDAY. EMERGENCY MANAGERS...HIKERS...CAMPERS AND THOSE WITH
OUTDOOR PLANS FOR THE REST OF THE WEEK SHOULD MONITOR FUTURE
FORECASTS CLOSELY.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

AZZ031-091200-
WESTERN PIMA COUNTY-
122 PM MST TUE JUL 8 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
ARIZONA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED THUNDERSTORMS WERE DEVELOPING OVER SOUTHEAST ARIZONA
THIS AFTERNOON. AT LEAST SOME OF THESE WILL SPREAD WEST INTO
WESTERN PIMA COUNTY TONIGHT. THE ATMOSPHERE IS A BIT MORE
UNSTABLE COMPARED TO YESTERDAY...SO A COUPLE OF STORMS COULD
PRODUCE WIND GUSTS APPROACHING SEVERE LIMITS ALONG WITH SOME
BLOWING DUST. MOISTURE IS BEGINNING TO INCREASE FROM THE SOUTH AS
WELL...SO A FEW STORMS MAY PRODUCE 1 TO 2 INCHES OF RAIN IN A
SHORT PERIOD OF TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A SIGNIFICANT INCREASE IN THUNDERSTORMS IS EXPECTED BEGINNING ON
WEDNESDAY AND CONTINUING INTO AT LEAST FRIDAY. A SURGE OF MOISTURE
IS SPREADING NORTH UP THE GULF OF CALIFORNIA...WITH A LOW PRESSURE
SYSTEM EXPECTED TO STALL OVER SOUTHERN ARIZONA BY THURSDAY. THIS
WILL INCREASE THE THREAT OF HEAVY RAIN AND FLASH FLOODING OVER PARTS
OF SOUTHEAST ARIZONA...WITH A FEW WET MICROBURSTS POSSIBLE MAINLY ON
WEDNESDAY. IT IS TOO EARLY TO TELL EXACTLY WHERE THE HEAVIEST RAINS
WILL FALL...BUT ISOLATED AMOUNTS OF 2 TO 4 INCHES ARE NOT OUT OF THE
QUESTION AT SOME POINT BETWEEN WEDNESDAY AFTERNOON AND FRIDAY.
EMERGENCY MANAGERS...HIKERS... CAMPERS AND THOSE WITH OUTDOOR PLANS
FOR THE REST OF THE WEEK SHOULD MONITOR FUTURE FORECASTS CLOSELY.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

PYTLAK